First, feed-grade L-lysine hydrochloride
(A) Identification
1. Reagents and solutions ninhydrin (Hg3-984-76): 0.1% (m / V) solution; silver nitrate (GB670-77): 0.1 mol / l solution; nitrate (GB62678): 1 +9 solution ; ammonium hydroxide (GB631-77): 1 +2 solution.
2. Identification of amino acids steps: Weigh 0.1 g sample, dissolved in 100 ml of water, take 5 ml of this solution, add 1 mL ninhydrin solution, heated three minutes later, add 20 ml of water, standing for 15 minutes, the solution purple was. Identification of Chloride: Weigh 1 g sample, dissolved in 100 ml water, add silver nitrate solution, that is, the white precipitate. Dilute nitric acid, insoluble precipitate; the other of white precipitate, adding an excess of ammonium hydroxide solution, precipitate dissolution.
(B) L-lysine hydrochloride determination
1. Reagents and solutions acid (Hg3-1296-80); glacial acetic acid (GB676-78); acid mercury (Hg3-1096-77): 6% (m / v) acetic acid solution; α-naphthol-phenyl-methanol Indicator: 0.2% acetic acid solution; perchloric acid (GB623-77): about 0.1 mol / L acetic acid standard solution.
2. Steps sample pre-dried at 105 ℃ to constant weight, weighed 0.2 grams of dried sample, weighed to 0.0002 g, add 3 mL formic acid and 50 ml glacial acetic acid, then add 5 ml of glacial acetic acid solution of mercury acetate. Add 10 drops of phenyl-α-naphthol instructions methanol solution with 0.1 mol / increase in acid, acetic acid standard solution titration, the sample liquid from the orange and yellow to yellow green shall titration end point. Otherwise the same method to correct the blank test.
3. The results calculated
C4H14N2O2 · HCl (%) (0.09132 × C · (V1-V2)) / m × 100
Type in C: the concentration of perchlorate standard solution, molar / L;
V1: perchloric acid consumed by the sample standard solution volume, ml;
V2: blank test the consumption volume of perchloric acid standard solution, ml;
m: sample mass, g;
0.09132: lysine per mmol of grams.
Second, feed-grade DL-methionine in the determination of
(A) Identification
1. Reagents and anhydrous copper sulfate solution: saturated solution of sulfuric acid; sodium hydroxide: 1 +5 solution; amino acid: 1 +100 solution; nitroprusside sodium cyanate: 1 +10 solution; hydrochloride (GB622-77): 1 +5 solution; ninhydrin: 2% (m / v) solution; acetate.
2. Steps weighed 25m g sample, add 1 ml anhydrous copper sulfate saturated sulfuric acid solution, yellow; weighed sample 5 mg